1. Field of the Invention
The present invention generally relates to the field of tools and methods for presenting music. The disclosure particularly pertains to tablet computers or other electronic devices used for digital sheet music display and music audio playback.
2. Description of Related Art
A couple of years ago sheet music publishers began to publish music also in paperless digital formats. With the release of tablet appliances such as the iPad®, many different digital software applications (hereinafter “apps”) for displaying sheet music have entered the market. The first of these apps displayed digital sheet music as stored in Portable Document Format (PDF) files. Soon afterwards these apps added the ability to annotate the sheet music with graphical markings. More recent apps added the capability, for use with suitable hardware platforms, to play an audio file simultaneously with displaying the sheet music.
Still later generations of tablet apps added more interactivity. For example, the NoteStar® app from Yamaha allows musicians to listen to music playing back in synchrony with a scrolling digital sheet music display.
So far all commercially available sheet music apps represent sheet music either in native app formats or standard cross-application formats like MusicXML and PDF files.
MusicXML files currently have no standard mechanism for synchronizing audio files to notation files for synchronized playback. Furthermore, MusicXML files represent music in a logical format structured around MIDI playback, rather than a visual format structured around display. This complicates the process of displaying sheet music on an electronic device in a form that captures the fine engraving details of a paper publication. In other words, the quality of the sheet music displayed on the electronic device is often poor if compared with a good paper publication of the same piece of music. For producing such paper publications huge efforts are often invested by the publishers to arrange the notes and other symbols in a manner that can be easily grasped by performers, students or music fans. This particularly applies to orchestral or other polyphonic music in which a plurality of parts are arranged one below the other on a single sheet to form a musical score.
The PDF format, on the other hand, is capable of representing sheet music in a high quality format. But since it does not contain, in contrast to the MusicXML format, any information that relates to the music as such, it has not been used to play an audio or video file simultaneously with displaying the sheet music.
For these reasons the sheet music apps currently available sacrifice, at least to some extent, the high layout quality of printed sheet music already available to the ability to play an audio or video file simultaneously with displaying the sheet music.
U.S. Pat. No. 7,239,320 B1 discloses a computer implemented method of presenting music to a user of an electronic device. This method makes it possible to display sheet music in a high quality graphical representation and to play an audio or video file simultaneously. To this end a hierarchical structure of bounding boxes is used to synchronize displayed sheet music to a musical performance recorded as audio or video file.
However, although this method is very helpful to compare a musical performance with corresponding sheet music, it cannot provide much help to musicians or students who want to improve their skills in performing a certain part in that piece of music. For example, if a chorister wants to better learn his part with the help of a good audio recording, it is usually difficult to clearly identify this part in the recording.
Prior art approaches use for such educational purposes a MIDI representation of the piece of music. Then it is easy to highlight a certain part by simply increasing the volume of the MIDI channel that corresponds to this particular part. But music produced on the basis of a MIDI file is often not satisfactory for a listener, because it lacks the charm and natural atmosphere of a recorded performance of real musicians. Amplifying a specific part in an audio recording is not possible because the audio recording is obtained by sampling an analog wave signal from which no specific parts can be isolated.